I think we can close this bug now. Sorry for not checking it with recent versions of VNC servers in the beginning - I did not have an opportunity back then...
-- darkpenguin
I've tried it with relatively recent versions of x11vnc and
tightvncserver on Debian Jessie and Linux Mint. It works. Apparently, it
doesn't work with older versions of various VNC servers on various
operating systems... but I don't think this is something that really
needs to be fixed.
